ASPEN - It was an adorable yet unexpected sight when a mama bear and her two cubs were spotted climbing down a tree in Aspen on Sunday before walking down the street as people watched nearby.

Steve Aben and his friend "Bradey" shot the encounter. To the average person, it may seem harmless, but experts say videos like this show how unnatural and unhealthy interactions between bears and humans have become.

Kent Drotar with the Wild Animal Sanctuary in Keensburg told us his response to the video.

"The first thing I felt was, that's too bad for the bear," he said. "They will start to come closer. If they're used to receiving food from somebody and someone doesn't give them food, they're going to get frustrated."

That's how people eventually get hurt, Drotar added.

Colorado has experienced several recent examples of brazen bears. A bear rummaged through a Parker family's patio in mid-August. Around two weeks later, a mama bear and her two cubs were euthanized at Apex Park in Jefferson County after hikers repeatedly reported their aggressive behavior.

"We've seen a lot more interactions between bears and humans for better or for worse," Drotar said.

As more people move to Colorado, more bears are facing a territorial dilemma:

"Do they stay on the edge of human society? Or do they get chased away by these bears that already have this territory?" Drotar questioned. "We have a lot more people that are going into areas where animals used to live or would like to live."